Chimeric protein

1. A chimeric protein having the formula:

Ht1 -Ht2-Casp

wherein

Casp is a caspase domain;

Ht1 is a first heterodimerization domain; and

Ht2 is a second heterodimerization domain

and wherein, in the presence of a chemical inducer of dimerization (CID), an identical pair of the chimeric proteins interact such that Ht1 from one chimeric protein heterodimerizes with Ht2 from the other chimeric protein, causing homodimerization of the two caspase domains.

2. A chimeric protein according to claim 1 wherein Ht1 does not heterodimerize with Ht2 within the same chimeric protein.

3. A chimeric protein according to claim 1 , wherein the caspase domain comprises an initiator caspase selected from the following group: caspase-8, caspase-9 and caspase-10.

4. A chimeric protein according to claim 1 , wherein the caspase domain comprises an executioner caspase selected from caspase-3 and caspase-7.

5. A chimeric protein according to claim 1 wherein one heterodimerization domain comprises an FK506-binding protein (FKBP) and the other heterodimerization domain comprises an FRB domain of mTOR.

6. A chimeric protein according to claim 5 , wherein Ht1 comprises FRB and Ht2 comprises FKBP.

7. A chimeric protein according to claim 5 , wherein the CID is rapamycin or a rapamycin analog.

8. A nucleic acid sequence which encodes a chimeric protein according to claim 1 .

9. A nucleic acid construct which comprises one or more nucleic acid sequence(s) according to claim 8 and a nucleic acid sequence encoding a T-cell receptor (TCR) or chimeric antigen receptor (CAR).

10. A nucleic acid construct having the structure:

Ht1-Casp-coexpr-Ht2-Ht2

wherein:

Casp is a nucleic acid sequence encoding a caspase domain;

Ht1 is a nucleic acid sequence encoding a first heterodimerization domain;

Ht2 is a nucleic acid sequence encoding a second heterodimerization domain; and

coexpr is a nucleic acid sequence allowing co-expression of Ht1-Casp and Ht2-Ht2,

wherein expression of the nucleic acid construct results in the production of a chimeric protein Ht1-Casp and an interfacing protein Ht2-Ht2 and wherein, in the presence of a chemical inducer of dimerization (CID), a pair of the chimeric proteins Ht1-Casp9 interact such that Ht1 from each chimeric protein heterodimerizes with an Ht2 domain from the interfacing protein, causing homodimerization of the two caspase domains.

11. A nucleic acid construct according to claim 10 , wherein Ht1 comprises an FK506-binding protein (FKBP) and Ht2 comprises an FRB domain of mTOR.

12. A nucleic acid construct according to claim 10 , which also comprises a nucleic acid sequence encoding a T-cell receptor (TCR) or chimeric antigen receptor (CAR).

13. A vector which comprises a nucleic acid sequence according to claim 8 which also comprises a nucleotide of interest.

14. A vector according to claim 13 , wherein the nucleotide of interest encodes a chimeric antigen receptor or a T-cell receptor, such that when the vector is used to transduce a target cell, the target cell co-expresses a chimeric protein according claim 1 and a chimeric antigen receptor or T-cell receptor.

15. A cell which expresses a chimeric protein according to claim 1 .

16. A cell which expresses two proteins:

Ht1-Casp and Ht2-Ht2

wherein Ht1-Casp is a chimeric protein comprising a caspase domain (Casp) and a first heterodimerization domain (Ht1); and Ht2-Ht2 is an interfacing protein comprising two second heterodimerization domains (Ht2)

wherein, in the presence of a chemical inducer of dimerization (CID), a pair of the chimeric proteins Ht1-Casp9 interact such that Ht1 from each chimeric protein heterodimerizes with an Ht2 domain from the interfacing protein, causing homodimerization of the two caspase domains.

17. A method for preventing or treating a disease in a subject, which comprises the step of administering to the subject,

(i) a cell which expresses a chimeric protein having the formula:

Ht1-Ht2-Casp

wherein

Casp is a caspase domain,

Ht1 is a first heterodimerization domain, and

Ht2 is a second heterodimerization domain

and wherein, in the presence of a chemical inducer of dimerization (CID), an identical pair of the chimeric proteins interact such that Ht1 from one chimeric protein heterodimerizes with Ht2 from the other chimeric protein, causing homodimerization of the two caspase domains; or

(ii) a cell which expresses two proteins:

Ht1-Casp and Ht2-Ht2

wherein Ht1-Casp is a chimeric protein comprising a caspase domain (Casp) and a first heterodimerization domain (Ht1) and Ht2-Ht2 is an interfacing protein comprising two second heterodimerization domains (Ht2)

wherein, in the presence of a chemical inducer of dimerization (CID), a pair of the chimeric proteins Ht1-Casp9 interact such that Ht1 from each chimeric protein heterodimerizes with an Ht2 domain from the interfacing protein, causing homodimerization of the two caspase domains.

18. A method according to claim 17 :

wherein the cell administered to the subject is a cell that was isolated from the subject and transduced or transfected with a vector encoding the protein or proteins.

19. A method according to claim 18 for treating cancer.

20. The method of claim 17 , which further comprises the step of administering rapamycin or a rapamycin analog to the subject if the subject shows signs of developing or having developed a pathological immune reaction caused by the administration of the cell.

21. A method according to claim 20 , wherein the pathological immune reaction is selected from the following group: graft-versus-host disease; on-target, off-tumour toxicity; immune activation syndrome; and lymphoproliferative disorders.